vm.runInNewContext global variable access is significantly slower

[srolel]

• Version: 8.17.0, 9.11.2, 10.21.0, 11.15.0, 12.20.0, 13.14.0, 14.16.0, 15.12.0
• Platform: 19.6.0 Darwin Kernel Version 19.6.0: Tue Jan 12 22:13:05 PST 2021; root:xnu-6153.141.16~1/RELEASE_X86_64 x86_64

What steps will reproduce the bug?

running:

const vm = require("vm");

const script = `
  (exports) => {
    exports.fn = () => {
      for (let i = 0; i < 10000; i++) {
        x;
      }
    };
  };
`;

global.x = 0;
eval(script)(exports);
console.time("eval");
exports.fn();
console.timeEnd("eval");

vm.runInNewContext(script, { x: 0 })(exports);
console.time("vm");
exports.fn();
console.timeEnd("vm");

results in:

eval: 0.251ms
vm: 1.124ms

How often does it reproduce? Is there a required condition?

consistently reproducible.

What is the expected behavior?

global variable access in new context should be approximately as fast as code running in global context.

What do you see instead?

global variable access in new context takes anywhere between 2x-10x more time than in global context.

[targos]

I think it's a duplicate of #31658

[srolel]

ah, seems like it, thanks! thought I searched thoroughly...